Magnetoresistance and magnetothermopower of nitrogen-annealed RE1.2Sr1.8Mn2O7+δ (RE=Nd, Pr)

Abstract We report measurements of resistance and thermopower of RE 1.2 Sr 1.8 Mn 2 O 7+ δ (RE=Nd, Pr) ceramics up to a magnetic field of 5 T. Nitrogen annealing has dramatic effects on the transport in reducing the resistivity, shifting peak resistivity to a higher temperature, and shifting thermopower to more negative values. The value of Δ JT increases as a result of nitrogen annealing, indicating an enhanced Jahn–Teller distortion due to the increased Mn 3+ concentration. These results are consistent with the effects of nitrogen annealing on the transport of RE=La.